20241226 finished.

src/problem/mod.rs

@@ -392,3 +392,5 @@ mod p855_exam_room;
 mod p1705_maximum_number_of_eaten_apples;
 
 mod p3218_minimum_cost_for_cutting_cake_i;
+
+mod p3083_existence_of_a_substring_in_a_string_and_its_reverse;

src/problem/p3083_existence_of_a_substring_in_a_string_and_its_reverse.rs

@@ -0,0 +1,45 @@
+/**
+ * [3083] Existence of a Substring in a String and Its Reverse
+ */
+pub struct Solution {}
+
+// submission codes start here
+use std::collections::{HashMap, HashSet};
+
+impl Solution {
+    pub fn is_substring_present(s: String) -> bool {
+        let s: Vec<char> = s.chars().collect();
+        let n = s.len();
+
+        let mut map = HashMap::new();
+
+        for i in (1..n).rev() {
+            let entry = map.entry(s[i]).or_insert(HashSet::new());
+            entry.insert(s[i - 1]);
+        }
+
+        for i in 0..n - 1 {
+            if let Some(set) = map.get(&s[i]) {
+                if set.contains(&s[i + 1]) {
+                    return true;
+                }
+            }
+        }
+
+        false
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_3083() {
+        assert!(Solution::is_substring_present("leetcode".to_owned()));
+        assert!(Solution::is_substring_present("abcba".to_owned()));
+        assert!(!Solution::is_substring_present("abcd".to_owned()));
+    }
+}